The present invention relates generally to the receiving of tokens and more particularly to the receiving and categorizing of those tokens as particular acceptable types or as being unacceptable according to their optically sensed size. The system has particular utility in public transportation systems, for example at a passenger entrance location where that passenger is required to deposit a fee in the form of one or more coins or a transit authority token.
The conventional fare box frequently encountered in mass transit systems includes a coin chute into which a passenger places a transit authority token or other tokens such as coins of varying monetary value with these tokens coming to rest on a flat plate where they may be inspected by a transit authority employee, such as the driver of a bus, streetcar or the like. Once the operator has confirmed that the appropriate fare has been deposited, he actuates a lever to dump the tokens from the inspection plate into an accumulating vault in the fare box pedestal preparatory to receiving further fares from the passengers.
Fare boxes of the foregoing type have long been in use and numerous modifications and improvements thereon have from time to time appeared. One such improvement is illustrated in U.S. Pat. No. 3,939,954 wherein deposited tokens are arranged serially or in single file to pass an optical sensing arrangement for determining the token diameter. One token edge is urged into engagement with a reference surface while the opposite token edge obscures certain light sensors while allowing light to pass from certain light sources to other of the light sensors with the particular sensors obscured or unobscured providing a measure of the position of the one coin edge relative to the reference surface. The accuracy of such an arrangement is highly dependent upon the coin or token being in engagement with the reference surface. The optical sensing arrangement which is typically an array of light emitting diodes and corresponding photo transistors provides only an indication of the lateral extent of one token edge which indication is presumed to be relative to the reference surface, with the other token edge engaging that surface.
Another variation on the classic fare box is illustrated in U.S. Pat. No. 3,918,565, wherein a property of the token material, such as a frequency shift due to a magnetic property thereof, is measured as the token is deposited. This measurement provides a single token parameter or a sequence of single token parameters indicative of a token material characteristic, such as its permeability or reluctance. After an analog to digital conversion, the token test result or results are compared to preset results and a decision on the validity and type of token is made. This system has no provision for size discrimination between tokens but rather relies on the token material characteristics. The system is further rather costly and requires frequent and careful maintenance, relying as it does on frequency or phase shift measurements and suffering from all of the problems associated with such measurements.